1. Field of the Invention
The present invention relates to a near-infrared-absorbing material suitable for use in the optoelectronics-related field, and to a near-infrared-absorbing filter using the same.
2. Description of Related Art
Various optoelectronic products, such as near-infrared-absorbing filters, use near-infrared-absorbing dyes that absorb infrared rays without substantially absorbing visible rays.
Depending on the conditions under which they are used, these optoelectronic products may be subjected to high temperature, high humidity or light irradiation, causing problematic decomposition of the near-infrared-absorbing dye contained therein.
Known techniques for improving resistance to such decomposition factors include changing the structure of the dye. For example, it is disclosed that a naphthalocyanine dye having a specific structure has excellent resistance properties (see, for example, Japanese Patent Laid-Open (JP-A) No. 2-4865, U.S. Pat. Nos. 4,960,538 and 5,024,926).
Techniques which involve using a near-infrared-absorbing dye in combination with an ultraviolet-absorbing material, thereby preventing decomposition due to light irradiation are also known (see, for example, JP-A No. 11-167350, JP-A No. 2001-133624, and JP-A No. 2005-181966).
However, the naphthalocyanine dye described above does not achieve a satisfactory balance between physical properties such as absorption wavelength and solubility, and is easily photodecomposed. Further, using the near-infrared-absorbing dye in combination with the ultraviolet-absorbing material is insufficient to prevent decomposition, and thus there is a demand for techniques that further improve resistance to light.
Accordingly, there is a need for a near-infrared-absorbing material that has excellent light resistance and invisibility, and is not prone to discoloration after photo-deterioration, and for a near-infrared-absorbing filter using the same.
Further, there is a need for a near-infrared-absorbing material that can be applied to optoelectronics-related fields, including application for near-infrared-absorbing filters, near-infrared-absorbing colored resin compositions, liquid crystal display elements, optical memory cards, optical recording media, and protective glasses.